Nanomechanical cantilever are small and extremely sensitive force and mass detectors. By coating (functionalizing) their surface with specific receptor molecules, cantilevers can be converted into highly sensitive and selective chemical sensors or label-free biosensors. The binding of the target molecules results in a bending of the cantilever caused by surface stress and/or in a shift of the cantilever’s resonance frequency due to mass load. Such sensors have e.g. been shown to be able to detect specific DNA sequences, proteins, small molecules or ions. We will present an instrument concept, which allows measuring with cantilever sensors at constant liquid flow rates. This allows to e.g. significantly expand the concentration range (dynamic range) of biosensor measurements, as will be shown for the example of different concentrations of specific DNA sequences. A second example will focus on the formation of a self-assembled monolayer of proteins on the cantilever surface under constant liquid flow. This kind of studies provide valuable information about dynamics of surface layer formation, rearrangements/relaxations within surface layers and the density of surface layers. All of these parameters are of major interest in the growing field of (bio-)chemical surface modification and functionalization of nanotechnological sensors and devices.